Hydroxyphenylalkyleneyl isocyanurates

ABSTRACT

NOVEL HYDROXYPHENYLALKYLENEYL ISOCYANURATES HAVE BEEN PREPARED. THESE COMPOUNDS STABILIZE ORGANIC MATERIALS AGAINST THE DELETERIOUS EFFECTS OF OXYGEN, HEAT AND LIGHT. THE STABILITY OF A-MONOOLEFIN HOMOPOLYMERS AND COPOLYMERS IS PARTICULARLY ENHANCED BY INCORPORATING STABILIZING AMOUNTS OF THE HYDROXYBENZYL ISOCYANURATES THEREIN.

v United States Patent 3,637,582 HYDROXYPHENYLALKYLENEYL ISOCYANURATESJack C. Gilles, Shaker Heights, Ohio, assignor to The B. F. GoodrichCompany, New York, N.Y.

N0 Drawing. Original application Oct. 25, 1968, Ser. No. 770,863, nowPatent No. 3,531,483, dated Sept. 29, 1970. Divided and this applicationDec. 29, 1969, Ser. No. 1,927

Int. Cl. C081? 45/60; C10m 1/32; C11b 5/00 U.S. Cl. 26045.8 N 22 ClaimsABSTRACT OF THE DISCLOSURE Novel hydroxyphenylalkyleneyl isocyanurateshave been prepared. These compounds stabilize organic materials againstthe deleterious effects of oxygen, heat and light. The stability ofOt-ITIOIIO'OICIIH homopolymers and copolymers is particularly enhancedby incorporating stabilizing amounts of the hydroxybenzyl isocyanuratestherein.

This is a division of application Ser. No. 770,863, filed Oct. 25, 1968.Ser. No. 770,863 is now U.S. Pat. 3,531,483.

BACKGROUND OF THE INVENTION Esters of cyanuric acid and isocyanuricacid, wherein the ester substituent is an aliphatic hydrocarbon radicalcontaining up to about 8 carbon atoms, are known. Tris-(2-hydroxyalkyl)isocyanurates have also been prepared, however, theprocess employed for their preparation, the reaction of isocyanuric acidand an alkylene oxide, is not suitable for providing hydroxyaryl(phenolic) isocyanurates. Aryl isocyanurates have heretofore beenlimited to the functionally unsubstituted benzyl isocyanurates.

SUMMARY OF THE INVENTION I have now prepared aryl isocyanurates whereinthe aryl substitutent is functionally substituted with a hydroxyl group.More particularly, the present invention relates to novel phenolicesters of isocyanuric acid, for example, to hydroxyphenylalkyleneylisocyanurates such as 4-hydroxybenzy1 isocyanurates. The isocyanuratering may be substituted with one, two or three hydroxyphenylalkyleneylgroups. The hydroxyphenylalkyleneyl radicals are alkyl substituted, thatis, they contain one or more alkyl radicals on the aromatic nucleus. Itis essential for the compounds of the present invention that theposition immediately adjacent to the hydroxyl group be substifulstabilizers for a wide variety of organic materials. They presentinvention will have the hydroxyl group hindered with a tertiary alkylgroup.

The present phenolic esters of isocyanuric acid are useful stabilizersfor -a wide variety of organic materials. They possess low volatility,are nonstaining .and are extremely effective protective agents fororganic polymeric materials, both natural and synthetic, which aresubject to the deleterious elfects of oxygen, heat and visible orultraviolet light. They are especially useful as stabilizers fora-monoolefin homopolymers and copolymers, particularly, polyethylene,polypropylene, ethylene-propylene copolymer and ethylene-propyleneterpolymers.

DETAILED DESCRIPTION The compounds of the present invention arerepresented by the general formula 3,637,582 Patented Jan. 25, 1972wherein m is an integer from 1 to 4, r is an alkyl group, eitheraliphatic or cycloaliphatic, containing from 1 to 18 carbon atoms andpositioned immediately adjacent to the hydroxyl group on the ring, and rr and r, are hydrogen or an aliphatic or cycloaliphatic group containingfrom 1 to 18 carbon atoms; and R and R are hydrogen or the same as Rabove. Especially useful isocyanuric acid esters are those compoundswherein two, and more preferably all, of the R groups arehydroxyphenylalkyleneyl radicals wherein r is a t-alkyl group containingfrom 4 to 12 carbon atoms, r is an alkyl group containing from 1 to 12carbon atoms, r and r, are hydrogen and m is 1, such as the3,5-di-t-butyl-4- hydroxybenzyl radical,3-methyl-5-t-butyl-4-hydroxybenzyl radical,2-methyl-5-t-butyl-4-hydroxybenzyl radical,3-t-butyl-5-methyl-2-hydroxybenzyl radical or like radicals.

The present invention encompasses the symmetrical tris(3,S-di-t-alkyl-4-hydroxybenzyl)isocyanurates which are a preferredclass of compounds and which may be represented structurally by theformula where n is an integer from 4 to 8. These compounds are excellentstabilizers for organic materials which are subject to oxidative,thermal and ultraviolet degradation, such as for example, natural rubberand olefin homopolymers and copolymers. They possess a good balance ofproperties useful for many stabilizing applications. It is mostsignificant with thesetris-(3,5-di-t-alkyl-4-hydroxyibenzyl)isocyanurates that although theyare high molecular weight, a necessary requirement if low volatility isto be achieved, the concentration of the hindered phenol grouping hasnevertheless been maintained at a high level (3 hindered phenolgroups/molecule). This permits lower levels of stabilizer to be employedwhich results in a considerable economic advantage for the user.

Typical of the 4-hydroxybenzyl isocyanurates within the scope of thepresent invention are:

tris-( 3-methyl-4-hydroxybenzyl) isocyanurate,

tris- 3-t-butyl-4-hydroxybenzyl isocyanurate,

tris- 3-t-amyl-4-hydroxyb enzyl isocyanurate,

tris- 3-octyl-4-hydroxybenzyl) isocyanurate,

tris-( 3 ,5 -dimethyl-4-hydroxybenzyl isocyanurate,

tris- 3,5 -diisopropyl-4-hydroxybenzyl) isocyanurate,

tris- 3-methyl-5-isobornyl-4-hydroxybenzyl isocyanurate,

tris (3-cyclohexyl-4-hydroxybenzyl) isocyanurate,

tris 3,5 -di-t-butyl-4-hydroxybenzyl isocyanurate,

tris- 3-t-butyl-5-t-amyl-4-hydroxybenzyl isocyanurate,

tris- 3 ,5 -di-t-amyl-4-hydroxybenzyl isocyanurate,

tris- 3,5-di-( l-methyll-ethylpropyl -4-hydroxybenzyl] isocyanurate,

tris- 3,5-di-( 1,1,2,2tetramethylpropyl) -4-hydroxybenzyl] isocyanurate,

tris-[3,5-di-(1,1-dimethylpentyl)-4-hydroxybenzyl]isocyanurate,

bis- 3-methyl-4-hydroxybenzyl isocyanurate,

bis- 3-t-butyl-4-hydroxybenzyl isocyanurate,

bis- 3 ,5 -dimethyl-4-hydroxybenzyl isocyanurate,

bis- (3 ,S-di-t-butyl-4-hydroxybenzyl isocyanurate,

3-Inethyl-4-hydroxybenzyl isocyanurate,

3-t-butyl-4-hydroxybenzyl isocyanurate,

3,5-dimethyl-4-hydroxybenzyl isocyanurate,

3,5-di-t-butyl-4-hydroxybenzyl isocyanurate,

and the like. It is not necessary that the ester substituents on theisocyanuric acid be identical, however, preparatively it is generallyeasier to obtain compounds wherein all the substituents are the same.

To obtain the 4-hydroxybenzyl isocyanurates of this invention an alkalimetal cyanate is reacted with a t-alkyl hindered p-hydroxybenzyl halidein an aprotic solvent, such as dimethyl sulfoxide orN,N-dimethylformamide, and at a temperature of about 100 to 130 C. It isessential that the alkali metal cyanate and the 4-hydroxybenzyl halidebe employed in equimolar amounts if the tris-(4-hydroxybenzyl)isocyanurate is to be obtained. The monoanddi-substituted isocyanurates can be obtained when excess alkali metalcyanate is employed for the reaction. Other preparative techniques mayalso be employed to obtain the present compounds, such as for example,the process described in US. Pat. 3,075,979.

The novel 4-hydroxybenzyl isocyanurates are high melting (above 200 C.)crystalline solids soluble in acetone, diethyl ether, dioxane,tetrahydrofuran, carbon tetrachloride, chloroform, aromatic hydrocarbonssuch as benzene, and toluene and slightly soluble in aliphatichydrocarbons and alcohols such as hexane, methanol and ethanol. They areinsoluble in water. The compounds will range in color from white to avery pale yellow when pure, however, if solvent or other impurities arepresent there can be appreciable color development upon exposure to air.

The present compounds find utility in that they are extremely effectiveprotective agents against the deleterious effects of oxygen, heat andlight for a wide variety of organic materials. This efficiency as astabilizer results at least partially from the ability of theisocyanurate ring to be substituted with up to three hindered phenolgroups, thus providing a high molecular weight compound whilemaintaining a high concentration of the hindered phenol.

Organic materials which are stabilized in accordance with the presentinvention include both natural and synthetic polymers. Thetris-(4-hydroxybenzyl)isocyanurates are useful for the stabilization ofcellulosic materials; natural rubber; halogenated rubber; homopolymersof ethylene; propylene, butene-l, isobutylene, pentene-l, hexene- 1,4-methyl-1-pentene and the like or copolymers thereof such asethylene-propylene copolymer, ethylene-butene-l copolymer,4-methyl-l-pentene-hexene-1 copolymer and the like;ethylene-propylene-diene rubbers wherein the diene is 1,4-hexadiene,2-methyl-1,4-hexadiene, a dimethyl-l,4,9-decatriene, dicyclopentadiene,vinyl cyclohexene, vinyl norbornene, ethylidene norbornene, methylenenorbornene, norbornadiene, methyl norbornadiene, methyl tetrahydroindeneand the like; conjugated diene polymers as for instance polybutadiene,copolymers of butadiene with styrene, acrylonitrile, acrylic acid, alkylacrylates or methacrylates, methyl vinyl ketone, vinyl pyridine, etc.,polyisoprene, polychloroprene and the like; vinyl polymers such aspolyvinyl chloride, polyvinyl fluoride, polyvinylidene chloride,copolymers of vinyl chloride with vinylidene chloride, polyvinylacetate, copolymers of vinyl halide with butadiene, styrene, vinylesters, c p-unsaturated acids and esters thereof, a,;8-unsaturatedketones and aldehydes, and the like; homopolymers and copolymers ofacrylic monomers such as acrylic acid, methacrylic acid, methylacrylate, methyl methacrylate, ethyl acrylate, 2-ethylhexyl acrylate,acrylamide, methacrylamide, N-methylolacrylamide, acrylonitrile,methacrylonitrile and the like; polyetheror polyol-derivedpolyurethanes; acetal homopolymers and copolymers; polycarbonates;polyesters such as those derived from maleic, fumaric, itaconic orterephthalic anhydrides or the like, for example, polyethyleneterephthalate; polyamides such as those derived from the reaction ofhexamethylenediamine with adipic or sebacic acid; epoxy resins such asthose obtained from the condensation of epichlorohydrin with bisphenols;and the like.

In addition to polymeric materials, the present compounds act tostabilize a wide variety of other organic materials. Such compoundsinclude: waxes; synthetic and petroleum derived lubricating oils andgreases; animal oils such as, for example, fat, tallow, lard, cod-liveroil, sperm oil, vegetable oils such as castor, linseed, peanut, palm,cotton seed and the like; fuel oil; diesel oil; gasoline; and the like.

The 4-hydroxybenzyl isocyanurates are especially useful for thestabilization of a a-monoolefin homopolymers and copolymers. Highandlow-density polyethylene, polypropylene, polyisobutylene, poly(4-methyl1 pentene) have excellent resistance to oxidative attack when stabilizedwith the compounds of the present invention. Ethylene-propylenecopolymers and ethylene-propylene terpolymers generally containing lessthan about 10% by weight of one or more monomers containing multipleunsaturation also possess excellent stability when stabilized with4-hydroxybenzy1 isocyanurates. Polymer blends, that is, physicaladmixture of two or more polymers may also be stabilized in accordancewith the present invention.

The amount of stabilizer employed will vary with the particular materialto be stabilized and also the particular 4-hydroxybenzyl isocyanurateemployed. Certain 4-hydroxybenzyl isocyanurates are more useful forcertain applications than others. This feature is attributable to thecompatibility of the isocyanurate with the organic material to bestabilized due to the difference in alkyl substitution on the phenolring or the number of phenol groups substituted on the isocyanuratering, that is, whether the isocyanurate be mono-, dior tri-substituted.Generally, however, for the effective stabilization of organic materialsan amount of the 4-hydroxybenzyl isocyanurate ranges from about 0.001%to about 10% by weight based on the weight of the organic material to beemployed. In most applications the amount of the compounds of thisinvention will vary between about 0.01% and about 5% by weight. With thepoly(a-monoolefin) homopolymers and copolymers about 0.01% to about 1.5%by weight of the stabilizer based on the weight of the olefin polymerwill be employed.

The compounds of the present invention are readily incorporated into theorganic materials to be stabilized and generally require no specialprocessing techniques. Conventional methods of incorporation have beenfound adequate. For example, the 4-hydroxybenzyl isocyanurates arereadily incorporated into the polymers by mixing on a rubber mill or ona Banbury mixer; or they may be added alone, in a suitable solvent, ormasterbatched with other ingredients to a solution or dispersion of thepolymer. The ready solubility of the compounds of this invention in awide variety of organic solvents facilitates their use in solution andalso renders them compatible with most oils and lubricants.

The 4-hydroxybenzyl isocyanurates are compatible with conventionalcompounding ingredients such as, for example, processing oils,plasticizers, lubricants, antisticking agents, fillers, reinforcingagents, sulfur and other curing agents, accelerators, antifoamingagents, rust inhibitors, pourpoint depressants and the like.

They are compatible with other known antioxidants, antiozonants, colorstabilizers, heat stabilizers, ultra-violet absorbers and the like.Often when employed in combination with known stabilizers, a synergisticeffect will be produced. Synergism will generally result when thep-hydroxybenzyl isocyanurates are combined with peroxide decomposingcompounds such as, (for example, dithiocarbamates, zincdialkylthiophosphates or organic sulfides such as those described in US.Pat. 2,519,755. Especially efiective to produce synergistic activitywith the compounds of the present invention are diesters offl-thiodipropionic acid having the formula wherein R is an :alkyl groupcontaining from 6 to 20 carbon atoms such as octyl, nonyl, decyl,lauryl, cetyl, stearyl, palmityl, benzyl, cyclohexyl and the like. Ithas been found advantageous when employing a p-hydroxybenzylisocyanurate/B-dia1kylthiodipropionate stabilizer system, that the[3-dialkylthiodipropionate be employed on an equal weight parts basis upto about 5 parts per part of the 4-hydroxybenzyl isocyanurate.

The following examples serve to illustrate the invention more fully. Allparts and percentages, unless otherwise indicated are on a weight basis.

EXiAMPLE X A glass reactor equipped with a stirred, condenser anddropping funnel was charged with 200 ml. of anhydrousN,N-dimethylformamide and 16.2 grams (0.2 mol) anhydrous potassiumcyanate suspended therein. The reactor and dropping funnel weremaintained under a nitrogen blanket throughout the run. The suspensionwas heated to 130 C. and 51 grams (0.2 mol)3,5-di-t-butyl-4-hydroxybenzyl chloride dissolved in 50 ml. dryN,N-dimethylformamide added dropwise over a two hour period. Thereaction mixture was heated with stirring for an additional hour,allowed to cool and poured into ice water.

benzyl)isocyanur-ate. Tris-(3,5-di-t-amyl 4 hydroxybenzyl)isocyanuratewas prepared following this procedure.

EXAMPLE II Bis (3,5 di-t-butyl-4-hydroxybenzyl)isocyanurate was preparedby suspending 121 grams potassium cyanate 1.5 mol) in 1 liter drydimethyl sulfoxide containing 10 drops tributyl phosphine. Thesuspension was heated to 95 C. and 234 grams (1 mol)3,S-di-t-butyl-4-hydroxybenzyl chloride dissolved in 250 ml. dimethylsulfoxide added over a three hour period followed by 9 hours additionalheating. The reaction mixture was cooled, poured into a large volume ofether and extracted with dilute hydrochloric acid, water and a saturatedsalt solution. Evaporation of the ether yielded 215 grams of a crudeproduct which recrystallized from ethanol and water and dried had amelting point of 257-258 C. Elemental analysis found 69.99% C, 8.19% Hand 7.44% N. Calculated forbis-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate is 70.2% C, 8.33% H and7.44% N.

EXAMPIJE III The isocyanuric acid ester substituted with a single 3,5-di-t-butyl-=4-hydroxybenzyl group was prepared by charging 20.8 grams2,6-di-t-butyl phenol (0.1 mol), 10 ml. water and about 200 ml.N,N-dimethylformamide to a reactor, heating to about 40 C. and adding12.9 grams cyanuric acid (0.1 mol), 3.5 grams para-formaldehyde (0.11mol) and approximately 1 gram hexamethylenetetramine. The temperature ofthe reaction mixture was raised to about 112 C. over a period of about 1hour followed by an additional hour of heating at 112 C. The contents ofthe reactor were poured into ice water and the solid collected byfiltration. The ether-soluble portion of this solid was washed withwater, sodium hydrosulfite and sodium chloride solutions before theether was evaporated. The solid, recrystallized several times fromhexane, had a melting point range of 254-258 C. Analysis by nuclearmagnetic resonance confirmed the product to be themono-substitutedderivative, 3,5-di-t-butyl-4-hydroxybenzyl isocyanurate.

EXAMPLE IV A conventional high-density polyethylene was stabilized withvarying amounts of tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, byitself and in combination with ,8- dilaurylthiodipropionate. Also, forcomparative purpose, several samples were stabilized using knownstabilizers which are commonly employed throughout the industry. Therecipes employed in these runs are set forth in Table I.

TABLE I Sample High-den sity polyethylene 100 Tris(3,5-dl-t-butyl-4-hydroxy-benzyl) isocyanurate The crude reactionproduct was recovered by filtration. Purification of thetris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate was achieved bymultiple extraction of an ether solution of the crude product with 5%aqueous sodium hydrosulfite, water and saturated salt solution. Theether was removed by evaporation and the product recrystallized frommethanol and water. 25 grams of the tris- 3,5 di-tbutyl-4-hydroxybenzyl)isocyanurate melting at 213215 C. was obtained.Infrared analysis showed a single carbonyl peak at 1710 cm. and nonitrogen-hydrogen linkages. Elemental analysis of the product agreedwith values calculated for tris-(3,5-di-t-butyl-4-hydroxywere thenplaced in a large test tube and aged in pure oxygen at 140 C. in amodified Scott tester block. The induction periods, that is, the timerequired for autooxidation of the polymer to occur, were recorded andare tabulated in Table II below.

Twenty-five mil molded samples were stapled onto 2" x 3" cardboard witha 1" hole in the center of the card. These cards were mounted in avertical position on stainless steel racks in an air-circulating ovenmaintained at 125 C. Every seven days the samples were scanned in theinfrared region for carbonyl (1200-2000 cmf build-up. The time at whichthe first noticeable increase in the carbonyl content was detected wasrecorded (see Table II). An increase in the carbonyl content isaccompained by embrittling of the polyethylene, in other words, thepoly- 1 Q lrlygen uptake so rapid at outest that accurate determinationnot pOSSl e.

2 Determined at 170 0.

EXAMPLE VIX A natural rubber white stock was prepared in accordethylenehas lost its useful character. ance with the following recipe:

TABLE 11 Sample 1 2 3 4 5 6 7 8 9 10 11 Induction time (hours) 0.5 35560 58 516 97 152 55 so 225 350 Carbonyl development (hours) 50 5, 5007,000 7,900 7, 900 6, 200 6,200 2,200 2,200 3,300 7,500

1 Test terminated at this point with no sample failure.

From the data in Table II, it is seen that tris-(3,5-di-t- Ingredient:Parts butyl.4-hydyoxybenzyl)isocyanurate is an excellent stabi- Naturalrubber 100 lizer for high-density polyethylene. The test results alsoStean'c acid 2 Show that the compounds of this invention compare favor-Zinc oxide 5 ably with commercially available hindered phenol stabi-Titanium dioxide 50 lizers. A synergistic effect is noted when thetris-(3,5-di-t- Sulfur 2.75 -butyl-4-hydroxybenzyl)isocyanurate is usedin combina- Benzothiazyl disulfide 1 tion withfl-dilaurylthiodipropiOnate. Similar stabilization Tetramethylthiuramdisulfide 0.1 of polyethylene was achieved with tris-(3,5-di-t-amyl-4-Tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurhydroxybenzyl)isocyanurate.ate 1 EXAMPLE V Tris (3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate wasincorporated in polypropylene in the same manner as described in ExampleIV. The test samples were prepared by molding the stabilized polymer at400 F. and 4000 psi. Ten mil samples are heated for 1 minute and 25 milsamples for 2 minutes before transferring to a cold press maintained at4000 p.S.i. for a 2 minute cooling period. Twenty-five mil samples wereaged in an air-circulating oven at 140 C. Samples were deemed to havefailed at the first sign of crazing. Table III sets forth the resultsobtained at several levels of stabilizer.

1 Test terminated at this point with no sample failure.

Unstabilized polypropylene crazed within one hour under these same testconditions.

EXAMPLE VI A copolymer of 4-methy1-l-pentene and 2-3 weight percenthexene-l was stabilized with tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate by itself and in combination withB-dilaurylthiodipropionate. Incorporation of the stabilizer in thepolymer, the oxygen absorption and oven aging tests were in accordancewith the procedure described in Example IV. Samples were prepared fortesting by molding the stabilized copolymer at 270 C. and 10 tonspressure for 15 minutes followed by a cold water quench. Thickness ofthe samples used in the oven aging was 12 mils instead of the customary25 "mils. Oven aging results obtained at 125 C. for the variousstabilized copolymer compositions is set forth in Table IV.

Press cured samples (290 F.) were aged in oxygen bombs maintained at C.for 4 and 7 day intervals. After 4 days aging thetris-(3,5-di-tbutyl-4-hydroxybenzyl)isocyanurate stabilized samples hada tensile strength of 2180 p.s.i. and an elongation of 560% as opposedto 1100 p.s.i. and 540% for an unstabilized sample. After 7 days agingthe unstabilized stock had degraded to a sticky mass, whereas thestabilized sample had a tensile strength of 2040 p.s.i. and 520%elongation.

EXAMPLE VIII A stabilized cis-polyisoprene polymer composition (AmeripolSN 600) was prepared by milling 1.3 gramstris-(3,5-di-t-rbutyl-4-hydroxybenzyl)isocyanurate into grams of the dryrubber. The unaged rubber had a Mooney viscosity (4 minutes) of 75 whichdecreased to 17 for the unstabilized rubber after 10 days air aging at70 C. After the same period of aging, the 4 minute Mooney of thestabilized cis-polyisoprene rubber was 33.

EXAMPLE IX Polyvinyl chloride (100 parts) containing 0.3 part stearicacid and plasticized with about 30 parts dioctyl phthalate wasstabilized with tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate andaged in a 375 F. air-circulating oven. The stabilized polyvinyl chloridesamples showed very little color formation during the first 30- 40minutes as opposed to the unstabilized samples which had become highlycolored in this same period.

EXAMPLE X The unplasticized polyvinyl chloride of Example IX containingno stabilizer evolved 0.1% hydrogen chloride within 12 minutes uponheating at 180 C. Stabilizing with 0.2 parttris-(3,S-di-t-butyl-4-hydroxybenzyl)isocyanurate, increased the timerequired to achieve the same evolution level to 16 minutes.

9 EXAMPLE XI A polymer blend of 75 parts chlorinated polyvinyl chloridehaving a density of 1.56 and 25 parts of a methylmethacrylate-butadiene-styrene copolymer compounded With 3 parts of atin stabilizer, parts titanium dioxide and 0.5 part of a lubricant wasmilled 4 minutes at 390 F. and then aged in a 400 F. forced air oven.Significant color change was noted after about 30-40 minutes and after50-60 minutes gassing was apparent. When 1 parttris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate was employed asadditional stabilizer and the sample tested, the first significant colorchange occurred after 75 minutes and no gas evolution was detected evenafter 120 minutes aging.

EXAMPLE XII A general purpose molding-gradeacrylonitrile-butadiene-styrene resin was stabilized with 0.5 parttris-(3,5- di-t butyl-4-hydroxybenzyl)isocyanurate in combination with1.25 parts tris-(nonylphenyl)phosphite. On oven aging at 160 C., thissample showed less color development after 20 minutes exposure than acomparable sample stabilized with 1.75 partstris-(nonylphenyl)phosphite.

EXAMPLE XIII 0.5 part tris-(3,5-di-t-butyl 4 hydroxybenzyl)isocyanuratewas added to an elastomeric polyurethane (Ketane 5740x140) containing0.5 part Tinuvin P and 0.5 part Agerite Stalite S. After aging thesample at 100 C. for one week, a 26% decrease in tensile strength and a16% increase in elongation, compared to the original polymer properties,was observed. This compared favorably with an identical polymercontaining 0.5 part of a commercial stabilizertetra[methylene-3-(3,5-di-t=butyl-4- hydroxyphenyl)propionate1methanesubstituted for the tris-(3,5 di-t-butyl-4-hydroxybenzyl)isocyanuratewhich had a 32% decrease in tensile strength with a 20% increase inelongation after the same exposure to aging. The unstabilized controllost 74% of its tensile properties within the same test period.

EXAMPLE XIV An ethyl acrylate-acrylonitrile (30%) copolymer latexstabilized with 0.5 part per hundred part rubber tris-(3,5-di-t-butyl 4hydroxybenzyl)isocyanurate was used to impregnate 11 mil uncoatedbleached craft paper by immersing the paper in the latex total solids)for seconds and then drip drying at room temperature. After aging for 7days in an oven maintained at 138 C. a reflectance reading of 58 wasobtained with the stabilized paper. Paper saturated with an unstabilizedcontrol latex gave a reflectance reading less than 50 under the sametest conditions.

EXAMPLE XV One hundred parts ethylene-propylene terpolymer comprising53% ethylene, 43% propylene and 4% ethylidene norbornene wasmasterbatched with 75 parts FEP black and parts naphthenic oil andcompounded as follows:

Ingredients: Parts Masterbatch 200 Zinc oxide 5 Stearic acid 1.0 Sulfur1.5 Mercaptobenzothiazole 1 .5 Tetramethylthiuram disulfide 0.8Dipentamethylene thiuram tetrasulfide 0.8

Tris (3,S-di-t-butyl-4-hydroxybenyl) isocyanurate 1.0

The vulcanizate after air-aging in a test tube at 150 C. for 21 days hadretained 98% of its original (unaged) tensile properties.

10 EXAMPLE XVI Unstabilized ethylene-propylene-methyl .tetrahydroindene(52/44/4) terpolymer samples containing 10 parts per million vanadiumcatalyst residue (sample 21) and 40 parts per million vanadium catalystresidue (sample 22) became sticky (degraded) after less thanl day agingat C. When the samples were stabilized with 0.1 parttris-(3,5-di-t-butyl 4 hydroxybenzyl)isocyanurate, the firstmanifestations of stickiness did not occur until after 16 days forsample 21 and after 4 days for sample 22.

EXAMPLE XVII A commercial ethylene-propylene-1,4-hexadiene terpolymer(Nordel 1040) became sticky after 17 days aging at 125 C., whereas, thesame polymer to which 0.2 parttris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate had been added ran for60 days before the first signs of stickiness.

EXAMPLE XVIII EXAMPLE XIX 'Styrene-butadiene copolymer (Ameripol 1511)was stabilized with 0.9 part tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate and air-aged at 70 C. The viscosity of thestabilized samples was not appreciably altered after 6 days aging. Anunstabilized polymer became hardened, indicating the development ofexcessive crosslinks, after less than one day aging under identicalconditions.

EXAMPLE XX.

The following compositions were stabilized with varying amounts oftris-(3,5-di-t-butyl-4-hydrozybenzyl)isocyanurate as follows:

Parts of Sample Material stabilizer 23 Polystyrene 0.5 24 Neoprenesponge..- 1.0 25 Cyclohexene 0.001 26 Mineral oil 0. 1 27 Syntheticlubricant 1.5

(Herculobe A).

All of the compositions set forth above showed improved oXidativestability over the unstabilized materials.

EXAMPLE XXI Bis-(3,5-di-t-butyl 4 hydroxybenzyl)isocyanurate as preparedin Example II Was employed to stabilize high density polyethylene, bothby itself and in combination with fi-dilaurylthiodipropionate. Thecompositions prepared were as follows:

Sample 29 30 31 Polyethylene 100 100 100 100 Bs-(3,5-di-t-butyl-4-hydroxyb nzyl 0. 1 0. 1

1socyan11rate B-Dilaurylthiodipropiouate. 0. 3 0. 3

The above samples were air aged at 170 C. The control 28 yellowed inapproximately one hour whereas the stabilized sample 29 ran for 24 hoursbefore appreciable yellowing and sample 30 had not yellowed even after100 hours. Sample 31 yellowed after about 48 hours. The same sampleswere also tested at C. for oxygen absorption.

Sample 29 had an induction period of 30 hours and sample 30 had aninduction period greater than about 300 hours. For the unstabilizedcontrol (28), autoxidation set in after less than hours.

The bis (3,S-di-t-butyl-4-hydroxybenzyl)isocyanurate exhibited astabilizing effect when tested in other polymeric materials such aspolypropylene, ethylene, ethylenepropylene-l,4-hexadiene terploymer,natural rubber, styrene-butadiene copolymer.

When the above example was repeated using is0cyanuric acid estersubstituted with a single 3,5-di-t-butyl-4- hydroybenzyl group, thepolyethylene had enhanced stability. The 3,5-di-t-butyl-4-hydroybenzylisocyanurate also exhibited a synergistic effect in polyethylene whencombined with p-dilaurylthiodipropionate.

EXAMPLE XXII Tris-(2-methyl-5-t-butyl 4 hydroxybenzyl)isocyanurate wasprepared using the procedure set forth in Example III, 12.9 grams (0.1mol) cyanuric acid and 24.98 grams (0.3 mol) 36% formaline were chargedto a reactor containing about 200 mls. N,N-dimethylformamide, 49.5 grams(0.31 mol) 6-t-butyl-m-cresol and about 1 gram hexamethylenetetraamine.The reactor and its contents were heated under a nitrogen purge to atemperature of about 110 C. and allowed to reset for 48 hours. Thereaction mixture was allowed to cool, poured into 12butyl-4-hydroxybenzyl)isocyanurate and excellent stabil ities achieved.

EXAMPLE XXIV A mixture of 2,6-di-t-butylphenol and 2t-butyl-o-cresolwere employed in the reaction with cyanuric acid and paraformaldehyde toobtain isocyanuric acid ester having mixed ester substituents. Theprocedure followed was similar to that described in Example III. 20.6grams (0.1 mol) 2,6-di-t-butylphenol and 32.8 grams (0.2 mol)2-tbutyl-o-cresol were dissolved in about 200 mls. N,N-dimethylformamidecontaining about 15 mls. water. To this was charged 12.9 grams (0.1 mol)cyanuric acid, 10.0 grams paraformaldehyde (calculated as 10% excessover 0.3 mol) and about 1 gram hexamethylenetetraamine. The reaction washeated for about 24 hours at a temperature ranging from 108 C. to 115 C.The cooled reaction product was then evaporated to dryness, dissolved inether and Washed successively with water, aqueous sodium hydrosulfiteand sodium chloride solutions. The ether was evaporated under vacuum andthe solid obtained recrystallized from ethanol. The product had amelting range of 163-170 C.

The product was incorporated in high-density polyethylene and inpropylene at levels and the samples aged. Compositions tested, testmethods and the test results are reported in Table V.

TABLE V Sample 32 33 34 35 36 37 38 30 40 41 42 Polyethylene 100 100Polypropylene 100 100 100 100 100 100 100 100 Product of Example XXI 0.1 0. 25 0. 1 1 B-Dilaurylthiodipropionate. 0. 2 0. 2 1 1 140 C. oxygenaging (inductlon period-hours) 35 56 600 125 C. air aging (carbonyldevelopment-hours) 216 1,026 1 7, 400 1,194 1, 914 3,186 3, 186

1 Test terminated at this point with no sample failure.

water and the resulting solid collected by filtration. Recrystallizationof the crude material from aqueous ethanol gave thetris-(Z-methyl-S-di-t-butyl-4-hydroxybenzyl)isocyanurate. Therecrystallized material was incorporated in high density polyethylene atvarying levels and exerted a stabilizing effect on the polyethylene.

EXAMPLE XXIII Tris-(3-methyl-5-t-butyl 4 hydroxybenzyl)isocyanurate wasprepared similar to Example XXII. The reactants employed were 12.9 grams(0.1 mol) cyanuric acid, 24.98 grams (0.3 mol) 36% formaline, 61.5 grams(0.373 mol) 6-t-butyl-o-cresol, 1 gram hexamethylenetetramine in about200 mls. N,N-dimethylformamide. The reaction was conducted for 24 hoursafter which time the reaction mixture was cooled and poured into icewater where a brownish green oil was formed. The oil was washed severaltimes with water and then extracted with ether. Removal of the etherunder vacuum yielded a yellowish solid, which upon recrystallizationfrom aqueous ethanol, yielded the white solid tris-(3-methyl-5-t-butyl 4hydroxybenzyl)isocyanurate melting at 148 to 150 C.

High-density polyethylene was stabilized with 0.1 part of the tris(3-methyl-S-t butyl-4-hydroxybenzyl)isocyanurate. The stabilized samplehad an induction period of 25 hours when aged at 140 C. in oxygen,whereas, the unstabilized control autooxidized in less than 1 hour. When0.2 part B-dilaurylthiodipropionate was employed in combination with thetris-(3-methyl-5-t-butyl-4-hydroxybenzyl)isocyanurate, the inductionperiod was increased to about 690 hours. This same stabilized samplelasted for 42 weeks in a forced-air oven maintained at C. beforedeveloping significant amounts of carbonyl. 'Ethylene propylenemethylene tetrahydroindene terpolymer was also stabilized with thetris-(3-methyl-5-t- EXAMPLE XXV An o-hydroxybenzyl ester of isocyanuricacid was obtained by reacting 49.2 grams (0.3 mol)2-t-butyl-4-methylphenol, 12.9 grams (0.1 mol) cyanuric acid and 9.5grams (0.3 mol) paraformaldehyde in 250 ml. N,N-dimethylformamide at 115C. This product (0.1 part) was incorporated in high-density polyethylenewhich was then aged at 125 C. in a forced-air oven. Carbonyl formationwas not detectable by infrared analysis until after 1850 hours, whereas,unstabilized, the carbonyl formation en sues after 50 hours. When 0.25part of the material was incorporated in polypropylene to be aged at C.,a composition having a very pronounced resistance to deterioration (456hours to crazing) was obtained.

EXAMPLE XXVI An epichlorohydrin-ethylene oxide copolymer (Hydrin 200)stabilized with 1 part tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanuratehad an induction period of 6.5 hours when aged at 140 C. in an oxygenatmosphere. The same polymer unstabilized immediately took up oxygen ata fast rate upon insertion into the oxygen chamber.

The above examples clearly illustrate the utility of the various4-hydroxybenzyl isocyanurates of this invention. The ability of thesematerials to stabilize a wide variety of organic materials, andparticularly organic polymeric materials, against the deleteriouseffects of oxygen, heat and light has been shown. The stabilization ofa-monoolefin homopolymers and copolymers particularly polyethylene,polypropylene and ethylene-propylene terpolymers has also beendemonstrated. Similar improved stabilities were obtained with cellulosicmaterials, polyamide (nylon 6), polyethylene terephthalate resin andpolytetramethylene terephthalate/isophthalate/sebacate copolyesterresins containing 0.5 part or less of the 4-hydroxybenzyl isocyanurates.

EXAMPLE XXVII To further demonstrate the effectiveness of the presentcompounds to be employed in combination with other known stabilizers, atris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyannrate/ 1,1,3 tris (2methyl-S-t-butyl-4-hydroxyphenyl) butane combination Was tested inpolypropylene. 15 mil polypropylene samples were prepared in theconventional manner and aged at 140 C. in a forced-air oven. Table VIsets forth the test results obtained for these stabilizer compositionsas well as results obtained for the individual stabilizer components. Itis evident that synergism is obtained. Similar synergistic activity wasobtained when the hydroxyphenylalkyleneyl isocyanurates were combinedwith other phenolic stabilizers which are well known to the art such asTABLE VI Sample Stabilizer components (parts per hundred polymerTris-(3,fi-di-t-butyl-i-hydroxybenzyDisocyanurate1,l,3-tris-(2-methyl-5-t-butyl-4- hydroxyphenybbutane Hours to crazing250 In addition to the compounds wherein isocyanuric acid serves as thenucleus for attaching the hydroxyphenylalkyleneyl groups, otherstructural related heterocychc compounds, that is, those having amolecular grouping in the ring, may be similarly substituted. Othersuitable nuclei includes: uric acid, hydantoin, allantoin, parabanicacid, alloxan, uracil, thymine, barbituric acid, phenobarbitone and thelike. For example, when 0.075 mol hydantoin, 0.15 mol 3,5-di-t-butyl-4-hydroxybenzyl chloride and 0.15 mol sodium bicarbonate were reacted at105 C. in N,N-dimethylformamide, the 3,5-di-t-butyl-4-hydroxybenzylradical was substituted on the hydantoin. This product was eifective asa stabilizer, by itself and in combination withfi-dilaurylthiodipropionate, for high-density polyethylene. At a 0.1part level in polyethylene aged in an air-circulating oven maintained at125 C., no carbonyl developed until after 6 /2 weeks aging whereas theunstabilized control failed in less than one week.

I claim:

1. A stabilized composition composition of matter Which comprises anorganic material subject to the deleterious eifects of oxygen, heat andlight and from about 0.001% to about 10% by weight of ahydroxyphenylalkyleneyl isocyanurate of the formula 14 wherein R is ahydroxyphenylalkylenyl radical having the formula wherein m is aninteger from 1 to 4, r is an alkyl group positioned immediately adjacentto the hydroxyl group on the ring and containing from 1 to 18 carbonatoms, and r 1' and r are selected from the group consisting of hydrogenor an alkyl group containing from 1 to 18 carbon atoms; and R and R areselected from the group consisting of hydrogen or R.

2. The stabilized composition of matter of claim 1 wherein r is atertiary alkyl group containing from 4 to 12 carbon atoms, r is an alkylgroup containing from 1 to 12 carbon atoms, r;., and r are hydrogen andm is l.

3. The stabilized composition of matter of claim 2 wherein the organicmaterial is a polymer.

4. The stabilized composition of matter of claim 3 wherein the polymeris an a-monoolefin polymer.

5. The stabilized composition of matter of claim wherein the polymer ispolyethylene.

6. The stabilized composition of matter of claim wherein the polymer ispolypropylene.

7. The stabilized composition of matter of claim 4 wherein the polymeris an ethylene-propylene-diene poly mer.

8. The stabilized composition of matter of claim 3 wherein r and r aretertiary alkyl groups containing from 4 to 8 carbon atoms.

9. The stabilized composition of matter of claim 8 wherein thehydroxyphenylalkyleneyl isocyanurate compound isbis-(3,S-di-t-butyl-4-hydroxybenzyl)isocyanurate.

10. The stabilized composition of matter of claim 8 wherein thehydroxyphenylalkyleneyl isocyanurate compound is tris- (3 ,5-di-t-buty1-4-hydroxybenzyl) isocyanurate.

11. The stabilized composition of matter of claim 8 wherein the polymeris an a-monoolefin polymer and there is employed an amount between about0.01% to about 5% by weight of the hydroxyphenylalkyleneyl isocyanurate.

12. The stabilized composition of matter of claim 11 wherein thehydroxyphenylalkyleneyl isocyanurate compound is bis (3,5 di-t-butyl 4hydroXybenzyDisocyanurate.

13. The stabilized composition of matter of claim 11 wherein thehydroxyphenylalkyleneyl isocyanurate compound is tris (3,5 di t butyl 4hydroxybenzyl)isocyanurate.

14. The stabilized composition of matter of claim 13 wherein the polymeris polyethylene.

15. The stabilized composition of matter of claim 13 wherein the polymeris polypropylene.

16. The stabilized composition of matter of claim 13 wherein the polymeris an ethylene-propylene-diene polymer.

17. A stabilized composition of matter which comprises (a) anu-monoolefin; (b) about 0.01% to about 5% by weight of ahydroxyphenylalkyleneyl isocyanurate of the formula wherein R is ahydroxyphenylalkyleneyl isocyanurate radical having the formula Is Itwherein m is an integer from 1 to 4, r is an alkyl group positionedimmediately adjacent to the hydroxyl group on the ring and containingfrom 1 to 18 carbon atoms, and r r and r are selected from the groupconsisting of hydrogen or an alkyl group containing from 1 to 18 carbonatoms; and R and R are selected from the group consisting of hydrogen orR; (c) from about 5 parts to 0.25 part per part of thehydroxyphenylalkyleneyl isocyanurate compound of a compound selectedfrom the group consisting of a fl-dialkylthiodipropionates of theformula ROOCCH CH S-CH CH COOR wherein R is an alkyl group containing 6to 20 carbon atoms and phenolic antioxidants.

18. The stabilized composition of matter of claim 17 wherein r of thehydroxyphenylalkyleneyl radical is a tertiary alkyl group containingfrom 4 to 12 carbon atoms, r is an alkyl group containing from 1 to 12carbon atoms, r and r are hydrogen and m is 1.

19. The stabilized composition of matter of claim 18 wherein thea-IIIODOOIefiI'l polymer is polyethylene.

References Cited UNITED STATES PATENTS 3,004,035 10/1961 Csendes260309.7 3,340,225 9/1967 Dressler 26045.8 3,392,141 7/1968 Blurnberg eta1 26045.7 3,425,984 2/1969 Patton et al. 26045.8 3,436,362 4/1969 Hayeret al. 26023.7 3,502,613 3/1970 Berger 26045.8

DONALD E. CZAJ A, Primary Examiner R. A. WHITE, Assistant Examiner US.Cl. X.R.

